184 
IOWA ACADEMY OP SCIENCE 
student has an opportunity of doing that work himself; in the rest of the insti- 
tutions the student who gets to 'dissect a brain during his college years can 
consider himself yery fortunate. It is not the fault of the teachers that the 
brain is not dissected systematically like the rest of the body, but it is mainly 
due to the fact that human brains are not very abundant in the dissecting rooms 
because so many are needed for the preparation of specimens for demonstra- 
tion. In those colleges where an attempt is made to have the students dissect 
the brain they are mostly told, 'after having finished cleaning the pia and 
vessels away, and having studied the sulci and gyri, that sections must be cut 
so and so, in order to get such and such a section, which corresponds to such 
and such a plate in the atlas, and then the identification of dark and light 
places commences. 
As far as the efficiency of the procedure alone, just imagine for a moment 
a complicated piece of . machinery imbedded in a large vessel of hot parafin 
of about the same shade, and after the thing is cooled you are asked to study 
that piece of machinery in different sections, which are made by slicing it. 
Is it not an enormous task to try to imagine a complete piece of machinery 
when you can only see a small portion at the time in a slice of it? How much 
more easily it would be to see or get a conception of the machine by scraping 
and working away the parafin from its delicate parts a portion at a time? 
Combined Method. 
It is just so with the brain and we can much more easily form an idea of 
its intricate arrangement by scraping its fibers. I prefer to break the brain 
tissue wherever possible, without destroying anything important, for the rest 
I follow its longitudinal or transverse fibers, as the case may be, by rolling 
them off carefully with a small orangewood stick,, the point of which is flattened 
and made smooth. The fibers must be scraped gently parallel to their longi- 
tudinal direction and in that manner all the tissue around them is removed. 
One of the things to be kept in mind is the difference in appearance between 
gray and white matter. All the ganglia of the base of the brain can be dis- 
sected by removing the white matter around them, and we certainly get an en- 
tirely different idea from the structures, as they present themselves in their real 
location, dimensions and relations. It is interesting to watch a student scrape 
the fibers of the commissura anterior, and to note the interest and fascination 
he shows to get the entire bundle of fibers and their communications out, with- 
out injury to them. It certainly stands to reason that the amount of attention 
which is required for a dissection of this kind makes a deeper impression upon 
the mind and also leaves a more vivid visual memory impression than the sim- 
ple cold study of the brain slices. I do not mean to say that I have discarded 
the slicing method altogether, because I realize that in some cases slicing 
may reveal more than teasing, but I maintain that in the greater number of 
instances scraping reveals the most, even in case of the fasciculus longitudinalis 
posterior, which is exceedingly hard to follow up. 
I always found it hard to demonstrate the capsula interna to the students in 
such a way that they would all grasp the whole thing, but now as I can show 
the exact course of the fibers between the nucleus caudatus and the nucleus 
lentiformis, it* becomes an easy task. 
I am aware of the fact that not all of the students can accomplish the same 
in this line of dissecting, for some of them are lacking in mechanical ability. 
